Effect of quartz particles and asphaltenes on the foamability and stability of non-aqueous foams

This study investigates the role of particles in non-aqueous foam stability by comparing the effects of inert (hydrophobic quartz) and surface-active (asphaltenes) particles in a kerosene/motor oil system. Using a dynamic Bikerman-based method, the influence of particle concentration and temperature on foamability and stability was quantified. Quartz particles exhibited a dual, energy-dependent role; at low gas flows, they acted as antifoams, at higher concentrations (>0.5%), they became effective stabilizers, attributed to the formation of a particle network that stopped liquid drainage. In stark contrast, asphaltenes displayed non-monotonic behavior, with an optimal, low concentration (0.008%) producing maximum stability; related to the transition from small colloidal aggregates to the formation of large flocs that break the inter-bubble film. Temperature has a complex effect: it is governed primarily by viscosity for quartz-laden foams, but it reveals a decoupling for asphaltene-containing foams, where higher temperatures (50 °C) improve both foamability and intrinsic stability (lower α₁/α₂ decay rates).